The present invention relates to an electronic endoscope system for capturing an object image using an image sensor and displaying an object image on a monitor device. More particularly, the present invention relates to an electronic endoscope system that is configured such that normal light illumination mode and a special wavelength light illumination mode can be switched.
An electronic endoscope generally includes a scope unit formed of a flexible tube, and an image signal processing unit, to which the scope unit can be detachably coupled. The scope unit is provided with an image sensor including a CCD (Charge Coupled Device) at a distal end of the flexible tube. An objective optical system is also provided at the distal end portion of the flexible tube, which forms an object image on the image sensor. Inside the scope unit, a light guide cable including optical fiber bundle is inserted. The distal end surface of the light guide cable faces an illumination lens, which is provided at the distal end of the scope unit. Further, the scope unit is formed with a treatment tool channel that allows treatment tools such as a forceps to go through. When in use, a treatment tool is inserted through the treatment tool channel, the distal end portion of the treatment tool being protruded from the distal end of the scope unit so that a desired treatment is performed.
In the image signal processing unit, a normal light source, i.e., a white light source such as a halogen lamp, xenon lamp or the like, is provided. When the scope unit is coupled to the image signal processing unit, the light emitted by the normal light source is incident on the proximal end surface of the light guide cable. When the scope unit is inserted in a cavity of a patient, the incident light proceeds in the light guide cable, and emerged through the illumination lens to illuminate an object facing the distal end of the scope unit. The light is reflected by the object, and converged by the objective optical system, which forms an optical image of the object on the light receiving surface of the image sensor. The image sensor converts the optical image to an electrical signal, which is transmitted to the image signal processor unit, where a video signal is generated and transmitted to the monitor device. Thus, the image of the object is displayed on the image screen of the monitor device.
Recently, in the field of the electronic endoscope, besides the normal light described above, light having a special wavelength is used as the illumination light for diagnosis and/or treatment.
An example of the diagnosis using light having the special wavelength is a fluorescent diagnosis using ultraviolet light as the illumination light for early detection of the cancer. It has been known that biotissues fluoresce when illuminated by the ultraviolet light, or excitation light having a predetermined wavelength. Healthy tissues emit stronger fluorescent light than the cancerous tissues. Therefore, by illuminating the tissues with the ultraviolet light (excitation light), and observing the fluorescent light emitted therefrom (i.e., a fluorescent image), the cancerous tissues can be detected at an early stage.
When the light having the special wavelength is used, an optional light guide cable for the special wavelength light becomes necessary. However, in view of the design of the scope unit, it is generally impossible to provide such an extra light guide cable inside the scope unit. Accordingly, in practice, the light guide cable for the special wavelength light is inserted in the treatment tool channel. That is, the proximal end of an extra light guide cable for the special wavelength light is coupled to a light source emitting the light having the special wavelength (e.g., an ultraviolet lamp or the like), and the extra light guide cable is inserted through the treatment tool channel. If, for example, a fluorescent image is to be observed, the excitation light is used for illuminating the object, and the fluorescent light emitted by the tissues is used for forming the optical image on the image sensor.
When the above-described diagnosis and/or treatment is carried out, it sometimes becomes necessary to switch the illuminating light between the normal light and the special wavelength light relatively frequently. In conventional electronic endoscope systems, the switching of the illumination light is carried out by an assistant operator who is different from an operator operating the scope unit. The assistant operator generally monitors operation of the entire system, and switches the illumination light following the directions of the operator. Since the directions are generally given by speech, if the illumination lights are to be switched frequently, it is very troublesome for the operator to give the directions to the assistant operator.
Further, according to another aspect, the normal light is used much more frequently than the special wavelength light. Therefore, it is preferable that the light source of the special wavelength light is turned ON/OFF appropriately. For example, if a diagnosis using the special wavelength light is to be performed after diagnosis using the normal light Is performed, it is preferable, for saving the energy and life of the light source, that the light source is turned ON immediately before it is used. Further, if the special wavelength light becomes unnecessary, the light source of the special wavelength light is preferably turned OFF immediately. Turning ON/OFF of the light source of the special wavelength light may be performed by the assistant operator. However, it is also troublesome for the operator of the scope unit to give the directions to the assistant operator, and it is preferable that turning ON/OFF of the light source of the special wavelength light Is done by the operator.
It is therefore an object of the invention to provide an improved electronic endoscope system, which uses the normal light and the light having a special wavelength as the illuminating light, and switching between the normal light and the light having the special wavelength can be done relatively easily by an operator.
Another object of the invention is to provide an electronic endoscope system, which uses the normal light and the light having a special wavelength as the illuminating light, and turning, ON/OFF a light source of the light having the special wavelength can be done easily by the operator.
According to an aspect of the invention, there is provided an electronic endoscope system including a scope unit for capturing an image of an object illuminated by light using an image sensor and an image processing unit that processes the captured image to generate a video signal, which is provided with a first illuminating system that illuminates the object with first light having a first characteristic, a second illuminating system that illuminates the object with second light having a second characteristic, at least one operable switch that is operated to instruct a switching between the first illuminating system and the second illuminating system, and a switching system that switches between the first illuminating system and the second illuminating system in response to the operation of the at least one operable switch. In this endoscope system, the at least one operable switch being provided at a portion accessible to an operator who operates the scope unit.
Since the operable switch is provided at a portion accessible to the operator who is operating the scope unit, switching between the normal light and the light having the special wavelength can be done relatively easily by the operator without asking an assistant operator to switch.
Optionally, the first illuminating system may include (a) a first light source that emits the first light, and (b) a first light guide cable inserted through the scope unit to guide the first light from the first light source to a distal end of the scope unit. Further, the second illuminating system may include (a) a second light source that emits the second light, (b) a second light guide cable inserted through the scope unit to guide the second light from the second light source to the distal end of the scope unit, and (c) a shutter provided between the second light source and the second light guide cable. With this structure, when the first illuminating system is selected, the shutter is closed so that the second light is not guided by the second light guide cable, and when the second illuminating system is selected, the shutter is opened to allow the second light to be guided by the second light guide cable and the first light source is turned OFF.
Alternatively, the first illuminating system may include (a) a first light source that emits light having a first characteristic, (b) a first light guide cable inserted through the scope unit to guide the first light from the first light source to a distal end of the scope unit, and (c) a first shutter provided between the first light source and the first light guide cable, and the second illuminating system may include (a) a second light source that emits light having a second characteristic, (b) a second light guide cable inserted through the scope unit to guide the second light from the second light source to the distal end of the scope unit, and (c) a second shutter provided between the second light source and the second light guide cable. With this construction, when the first illuminating system is selected, the second shutter is closed so that the second light is not guided by the second light guide cable, and the first shutter is opened to allow the first light to be guided by the first light guide cable, and when the second illuminating system is selected, the first shutter is closed so that the first light is not guided by the first light guide cable, and the second shutter is opened to allow the second light to be guided by the second light guide cable.
Further optionally, the first illuminating system may include a first light source that emits light having a first characteristic, the second illuminating system may include a second light source that emits light having a second characteristic, and the electronic endoscope may further include a controlling system that controls the second light source to turn ON and OFF. With this construction, if the second light source is turned OFF and the at least one operable switch is operated in a predetermined manner, the second light source is turned ON, and if the second light source is turned ON and the at least one operable switch is operated in the predetermined manner, the second light source is turned OFF.
According to another aspect of the invention, there is provided an electronic endoscope system including a scope unit for capturing an image of an object illuminated by light using an image sensor and an image processing unit that processes the captured image to generate a video signal. The electronic endoscope may further include a first illuminating system that illuminates the object with white light, a second illuminating system that illuminates the object with light having a special wavelength, at least one operable switch that is operated to instruct a switching between the first illuminating system and the second illuminating system;
a switching system that switches between the first illuminating system and the second illuminating system in response to the operation of the at least one operable switch, the at least one operable switch being provided at a portion accessible to an operator who operates the scope unit.
Optionally, at least one operable switch may include a foot switch which can be operated by a foot of the operator.
Further optionally, the scope unit may be provided with an instrument channel through which a treatment tool can be inserted, the at least one operable switch including a manually operable switch arranged adjacent to an inlet of the instrument channel.
Furthermore, the scope unit may have an operation section, at which operation switches are provided, and at least one operable switch may include another manually operable switch arranged at the operation section.
Still optionally, the first illuminating system may include (a) a white light source that emits white light, and (b) a light guide cable inserted through the scope unit to guide the white light from the white light source to a distal end of the scope unit, and the second illuminating system may include (a) a special wavelength light source that emits light having a special wavelength, (b) another light guide cable inserted through the instrument channel to guide the light having the special wavelength from the special wavelength light source to the distal end of the scope unit, and (c) a shutter provided between the special wavelength light source and the another light guide cable. With this construction, when the first illuminating system is selected using the at least one operable switch for illuminating the object, the shutter is closed so that the special wavelength light is not guided by the another light guide cable, and when the second illuminating system is selected using the at least one operable switch for illuminating the object, the shutter is opened to allow the light having the special wavelength to be guided by the another light guide cable and the white light source is turned OFF.
Alternatively, the first illuminating system may include (a) a white light source that emits white light, (b) a first light guide cable inserted through the scope unit to guide the white light from the white light source to a distal end of the scope unit, and (c) a first shutter provided between the white light source and the light guide cable, and the second illuminating system may include (a) a special wavelength light source that emits light having a special wavelength, (b) a second light guide cable inserted through the instrument channel to guide the light having the special wavelength from the special wavelength light source to the distal end of the scope unit, and (c).a second shutter provided between the special wavelength light source and the second light guide cable. With this construction, when the first illuminating system is selected using the at least one operable switch for illuminating the object, the second shutter is closed so that the special wavelength light is not guided by the second light guide cable, and the first shutter is opened to allow the white light to be guided by the first light guide cable, and when the second illuminating system is selected using the at least one operable switch for illuminating the object, the first shutter is closed so that the white light is not guided by the first light guide cable, and the second shutter is opened to allow the light having the special wavelength to be guided by the second light guide cable.
Further optionally, a performance of the image processing unit is changed in accordance with the operation of the at least one operable switch so that an appropriate image processing operation is performed depending on a selected one of the first and second illuminating systems. In this case, the image processing unit may include an amplifier that amplifies image signals output by the image sensor, a gain of the amplifier when the second illuminating system is selected being higher than a gain when the first illuminating system is selected.
Optionally, the light having the special wavelength is UV light.
In a particular case, the first illuminating system may include a white light source that emits white light, the second illuminating system may include a second light source that emits light having a special wavelength, and the electronic endoscope may further include a controlling system that controls the second light source to turn ON and OFF. With this construction, if the second light source is turned OFF and the at least one operable switch is held operated for a predetermined duration of time, the second light source is turned ON, and if the second light source is turned ON and the at least one operable switch is held operated for a predetermined duration of time, the second light source is turned OFF. Further, in this case, at least one operable switch including a foot switch which can be operated by a foot of the operator.
Still optionally, the scope unit may be provided with an instrument channel through which a treatment tool can be inserted, and at least one operable switch may include a manually operable switch arranged adjacent to an inlet of the instrument channel.
Further optionally, the scope unit may have an operation section, at which operation switches are provided, and at least one operable switch may include another manually operable switch arranged at the operation section.